The present invention relates to an interior illumination apparatus which is provided on a ceiling or the like in a passenger compartment of a vehicle for illuminating the interior of the passenger compartment.
As a related interior illumination apparatus of this type, US2005/0168998A1 (corresponding JP patent application: JP-A-2005-125870) discloses an interior illumination apparatus. As shown in FIGS. 7 and 8, an interior illumination apparatus 100 includes a design part 101 which is fixed to an interior side of a ceiling trim (not shown) belonged to members of a vehicle's side, a function attaching member 110 which is fixed to an exterior side of the design part 101 with first attaching units 140 disposed in a plurality of locations, a pair of left and right lens rotary elements 120 which are rotatably accommodated in the design part 101 and the function attaching member 110, and a pair of left and right function parts 130 which are attached to the function attaching member 110 with second attaching units 150 disposed in a plurality of locations.
The design part 101 has a housing 102, and left and right lens holes 103 and operation accommodation holes 104 are formed in the housing 102. Surface sides of the lens rotary elements 120 are exposed from the respective lens holes 103. A switch operating portion 105 is disposed movably in each operation accommodation hole 104. The function parts 130 have a pair of left and right switch portions 131 and a pair of left and right lamps 133 which are turned on and off by the respective switch portions. The switch portions 131 are connected to the corresponding switch operating portions 105, and on and off operations of the lamps 133 are performed by the switch operating portions 105 accordingly. The lamps 133 are individually disposed in positions which correspond to the lens rotary elements 120. A light emitted from the individual lamps 133 passes through the corresponding lens rotary elements 120 so as to enter into the interior of the passenger compartment for illumination thereof. In addition, wiring harnesses WH are connected to the function parts 130 for power supply from the body side.
Each first attaching unit 140 includes a locking projection 141 provided on the housing 102 of the design part 101 and a locking frame portion 142 provided on the function attaching member 110, and the locking projection 141 is locked to the locking frame portion 142. Each second attaching unit 150 includes a locking projection 151 provided on the function part 130 and a locking frame portion 152 provided on the function attaching member 110, and the locking projection 151 is locked to the locking frame portion 152.
Next, an example of assembling work of the related interior illumination apparatus will be described. The design part 101 is fixed from the interior side of the ceiling trim (not shown) in a position on the ceiling trim where an attaching hole is provided. The left and right lens rotary elements 120 are set on the design part 101, and the function attaching member 110 is assembled to the design part 101 from the exterior side of the ceiling trim, the respective first attaching units 140 being put in locking states, whereby the function attaching member 110 is attached to the design part 101. Next, the pair of left and right function parts 130 to which the wiring harnesses WH are connected are assembled to the function attaching member 110 from the exterior side of the ceiling trim. As a result, the respective second attaching units 150 are put in locking states, whereby the left and right function parts 130 are attached to the function attaching members 110. Next, the switch operating portions 105 are individually inserted into the corresponding operation accommodation holes 104, and the respective switch operating portions 105 are connected to the corresponding switch portions 131.
When the user depresses either of the left and right switch operating portions 105, the corresponding switch portion 131 is operated, whereby the corresponding lamp 133 is turned on or off.
As is seen from the assembling work described above, the design part 101, the function attaching member 110 and the function parts 130 can be assembled sequentially in that order, and since locking is implemented between the members following the order described above, that is, between the design part 101 and the function attaching member 110, and between the function attaching member 110 and the function parts 130, good assembling properties are provided.
However, since the function parts 130 are positioned with respect to the design part 101 via the function attaching member 110, the positioning of the function parts 130 relative to the design part 101 is affected by a dimension error of the function attaching member 110 itself and assembling errors between the function attaching member 110 and between the design part 101 and the function parts 130. Because of this, the positioning accuracy between the function parts 130 and the design part 101 is not good, causing a fear that the switch operating portions 105 which are connected to the switch portions 131 are not situated in the proper positions in the operation accommodation holes 104. In the event that the switch operating portions 105 are not positioned in the proper positions in the operation accommodation holes 104, there is caused a problem that the operating properties of the switch operating portions 105 are deteriorated. In addition, in the event that gaps between outer circumferential surfaces of the switch operating portions 105 and the operation accommodation holes 104 are not uniform, the appearance is also deteriorated.